inevitability of it. parkinson's is a very gradual disease, but inevitably it's going to get you. >> lift your eyes. >> you go through a period of adjusting when you realize your life is going to be different than you had imagined. >> narrator: life changes for parkinson's patients when a key neurotransmitter called dopamine goes missing. >> put your hands inside your knees. >> narrator: dopamine is like the oil that lubricates your motor system. without it, muscles stiffen, arms shake. sometimes you stutter and stop. >> by counting your steps, you break up that festination problem. >> one, two, three, four, five, six, seven, eight. >> narrator: drugs help for a while, and a new surgical technique called deep brain stimulation can relieve symptoms for several years. >> and go, and go, and go. >> narrator: but the disease is progressive, and there is no cure. >> roll to your right. >> narrator: tom shearer has had parkinson's for 15 years, and early on he coped well.